WHAT IS (AND WHAT ISN'T) STREAM RESTORATION?

Stream restoration is a relatively new approach in river management that attempts to return a stream to a stable condition, reduce bank erosion, and improve aquatic habitat. Stream restoration, unfortunately, has also become a catch-all phrase applied to all river management practices, including those that create channel instability. To be truly meritorious of the designation “stream restoration”, a project must return the restored reach to an equilibrium condition while minimizing upstream and downstream impacts.

In-stream structures, soil bioengineering, and natural channel design are stream restoration techniques that can improve habitat, reduce erosion, and create channel stability, respectively. These techniques, however, can cause instabilities and off-site impacts if used without a full understanding of the past, current, and future conditions in the surrounding watershed. Stream restoration projects meet with greater success when done in conjunction with a geomorphic assessment that unravels the natural watershed conditions and human land use activities that are affecting stream equilibrium.

Natural stream channels are typically sized to convey peak storm discharges that occur once every year or two. As such, stream restoration projects attempting to recreate this natural condition are prone to failure during large storms. The likelihood of failure is greatest in the first year or two after project construction and before bank resistance has developed through the growth of riparian vegetation. Stream restoration holds many benefits for improving habitat and reducing property damage. However, without a complete understanding of what stream restoration is and under what conditions it should be used, river managers can potentially worsen the existing condition and turn public support away from a promising new approach to river management.